Camper shell or bedrack with rooftop tent. Better MPG?

I have to say that I have really enjoyed a basic Leer shell on our "long bed" SR. I made very specific decisions to preserve MPG, like getting a cab-hi camper shell, kept the tires at 245/75-16 (but E-load Firestone Destination X/Ts) and it still gets 24-25 MPG at 65-70 MPH and still around 20-21 at 75-80 MPH (2.7-liter here). I don't think the camper shell affected MPG at all and I lost about 1 MPG all around with the tires. I'm not lifting it or putting any protrusions on it... it was plenty capable in Colorado stock.

I wanted to be able to sit up inside which meant no drawers or platforms, and I didn't want the MPG hit from a hi-top camper shell, so I put a 20" deep shelf up at the front of the bed. Then, when you get in, you just throw all your stuff up there so it's not in the way. We didn't do any kind of fancy storage solution, we just have about six or eight of these plastic stackable bins for supplies. They ride under the shelf when driving, then we put them on the shelf when we get in. You can kind of sit up against it/rest your back on it but we normally sleep with our heads by the tailgate. I would prefer to have my head toward the cab but don't want to wake up and slam my head into the bottom of the shelf.

We have the Toyota rubber mat, then some Thermarest pads and then a cheap memory foam bed topper on top and sleep great in it. It was so great in Colorado when we were doing dispersed camping... just find a spot, roll up and get in the back with no setup. It's so nice when it's raining or cold (it is 99% rain- and wind-proof... after a lot of sealing) and if you need to leave when it's raining in the morning, you just hop out, get in the front and leave.

I used some L-brackets from Home Depot and got some T-nuts for the side rails. You do have to put the shelf through one of the camper shell's side windows (requires taking the screen off) as the shelf will be wider than the rear door opening.

My carpentry skills are super basic - don't judge - but this works great for us

 

What type of camper shell is that, or who makes it?